People of Interest: Giovanni Battista Venturi March 15, 1746 – April 24, 1822

Giovanni Battista Venturi was born in 1746 to an affluent family in Reggio, Italy. An aspiring student, Giovanni was ordained as a priest and a professor by the age of 23. An avid historian of science at the University of Modena, he was the first to emphasize Leonardo da Vinci as a scientist rather than just an artist as he’s more commonly known. Despite his love for history, it wasn’t long before the University of Modena became aware of his talents in mathematics where they appointed him as professor of geometry and philosophy in 1774. During his tenure at the University of Modena, Giovanni was promoted to the Professor of Experimental Physics, served as the Duke of Modena as the State engineer and auditor, later serving diplomatic roles in both France and Switzerland.

Giovanni is most well-known for his work in developing what is now known as the venturi effect. In 1797, he published a study on the flow of water through short cylindrical tubes. It wasn’t until 1888 that Venturi’s design was applied to something practical when a man named Clemens Herschel received a patent for the first commercial venturi tube. The original purpose of the venturi tube was to measure the amount of water used in individual water mills and is still used to this day as a means of measuring fluid flows.

Venturi tube.jpg
Venturi Tube

The venturi effect is a principle in fluid dynamics and states that a fluid’s velocity must increase as it passes through a constricted pipe. As this occurs, the velocity increases while the static pressure decreases. The pressure drop that accompanies the increase in velocity is fundamental to the laws of physics. This is known as Bernoulli’s principle. Below is an illustration of how the venturi effect works inside of a constricted tube.

venturi

In everyday life, the venturi principle can be found inside of many small engines such as lawn mowers, gas powered scooters, motorcycles and older style automobiles. Inside the carburetor, there is a small tube through which filtered air flows from the intake. Inside of this tube is a short narrowing. When the air is forced to constrict, its velocity increases and creates a vacuum. This vacuum draws in fuel and mixes with the air stream causing it to atomize.  As the throttle valve is opened further, more fuel is forced into the engine. This increases the RPM and creates more power.

inlineworks
In-Line E-Vac

This principle is also applied to EXAIR’s line of E-Vac products to create vacuum. The .gif below illustrates how an In-Line E-vac works. (1) Compressed air flows through the inlet (2) and is directed through a nozzle, constricting the flow of air. (3) As the air stream exhausts, it expands causing a decrease in pressure and an increase in velocity prior to passing through the venturi. (4) A vacuum inlet tangential to the primary airflow is located at the suction point between the orifice and the venturi. (5) The airflow that is drawn through the vacuum inlet mixes with the primary airstream, then exhausts on the opposite end.

The venturi effect is used in a variety of other EXAIR products used for cooling, drying and cleaning, in addition to the vacuum generators. If you have a process in your facility that may benefit from an Intelligent Compressed Air solution, give us a call. We’d be happy to discuss your application and implement a solution to both reduce your compressed air costs and improve worker safety.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD

Photo: Venturi Tube with labels by ComputerGeezer an Geof.  GNU Free Documentation License

Building an E-Vac Vacuum Generator System

EXAIR’s In-Line and Adjustable E-Vacs are a powerful compressed air powered vacuum generator. They’re a low-cost way to create a vacuum for a variety of different applications: pick and place, clamping, chucking, lifting, surface mounting, and vacuum forming are just some of the possibilities. Both the In-Line and Adjustable E-Vacs are available in a variety of different sizes and flows and can accommodate a wide range of applications.

With no moving parts to wear out, EXAIR’s E-Vacs are virtually maintenance free when supplied with clean, dry compressed air. In-Line E-Vacs are available in two different styles: High Volume, Low Vacuum for use with porous materials and Low Volume, High Vacuum for use with non-porous materials.

For pick and place or lifting applications, vacuum cups will be necessary. With a wide variety of different vacuum cups available: Small Round, Large Round, Oval, and Bellows, we can accommodate nearly any size or shape material. For heavier materials, round cups with cleats provide rigidity and ensure that the load remains stable. For applications on textured or uneven surfaces, Bellows style cups have convolutions that allow for the cup to quickly decompress when it touches the surface of an uneven part or material. To determine the most suitable cup, we must consider the weight of the material and the orientation it will be lifted.

Vacuum cups

If it is being lifted with the vacuum cups positioned horizontally, use a safety factor of 2. For applications where the part or material will be lifted vertically, use a safety factor of 4. This safety factor is then multiplied by the weight of the material. You’ll then need to determine how many vacuum cups are needed. No more than 4 vacuum cups should be used with any one E-Vac. Consider the size/shape of the material to be lifted and place vacuum cups accordingly to evenly distribute the weight. Heavier and larger materials may necessitate the use of more than one E-Vac.

The weight a particular cup can hold at a given pressure is shown in the chart below. Once you’ve determined a suitable cup based on the weight and orientation of the lift, a variety of other accessories are also available.

vacuum cup weights

The vacuum port of the E-Vac has an NPT thread, vacuum cups can be installed directly in this inlet. For applications where the vacuum cup(s) are remotely located, we offer polyurethane vacuum tubing as well as a variety of different fittings to connect them. Both 1/4” and 3/8” O.D. sizes are available in 10’ lengths up to 50’. Simply indicate the model number of the tubing and add the length with a “-“ at the suffix. In addition to fittings and tubing, vacuum check valves are also available. These can be beneficial if there is potential for fluctuations in the compressed air pressure or supply. In the event that there is a significant drop in pressure or loss of compressed air supply, the check valve will ensure that the load remains stable.

To minimize the sound level and ensure you’re adhering to OSHA 1910.95, we have Standard Mufflers as well as Straight Through Mufflers. The Straight Through Mufflers offer the best level of sound reduction, up to 26 dBA!!

E-Vac Mufflers

With all of the different options making a selection can seem like a daunting task. If you’re struggling to determine the most suitable E-Vac and Accessories for your application, give an Application Engineer a call today!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@Exair.com
Twitter: @EXAIR_TD

I Pick Things Up & I Put Them Down

This past weekend in Columbus, OH was a sporting event hosted by Arnold Schwarzenegger.  This event has many aspects of it and this past weekend was the first year where spectators were not permitted due to the COVID-19 risks and scares.  The caterer for the event had already prepped all of the food to prepare for thousands of people so instead of donating locally, they connected with head chefs in Nashville, TN to create a “tailgate extravaganza” to try and lift the community up after the recent tornado and storms ravaged the area and demolished homes as well as communities.  The Arnold still happened, with participants only, they were all, “Picking Things Up and Putting Them Down.”

Arnold Sport’s World Record Lift

Seeing these giant athletes perform deadlifts always reminds me of the EXAIR Adjustable E-Vacs and how they are used frequently to pick things up and put them down.  When determining the correct Adjustable E-Vac I always like to start with the shape, weight, and surface of the part.  This is how I determine which vacuum cup can be utilized.  The good news is as a customer, the choice doesn’t have to be made alone, that is why the Application Engineering team is here, we’ll help you determine which vacuum cup will suit the given application.

These are all examples of how an E-Vac pick-and-place system is just a solenoid valve away from automation.

Some of the factors we use to determine the suction cup is listed out below.

Is the lift going to be a vertical cup lift or a horizontal cup lift?  This means is the face of the cup vertical, picking up a box from the ground by the sides, or is it going to be horizontal where the face of the cup sits horizontally over the part.

For a vertical cup face, if lifting the part up vertically then a bellows cup will not be suitable and something with a cleat will be needed due to the rigidity of the cup to help keep the cup and part stable.  The bellows may collapse due to the weight of the product, where the cleats will interface with the part and create a solid connection to aid in the lift.

For a horizontal cup face, if lifting the part up vertically then a bellows cup would work ideal in the event the surface is uneven.  Maybe one end is slightly taller, in this scenario, a bellows cup would help the cups to all seal to the surface and still be able to pick up the item.  These cups are also thinner to help adapt to an irregular surface on the part or to help keep suction if the part deforms upon being picked up. The bellows is not recommended for rather heavy objects as the bellows may collapse under extensive load and cause the cup to lose suction.

Talking about the weight of the item, this also becomes a major factor as each cup has a maximum lifting weight and that is determined by the surface area of the cup as well as whether it has cleats, bellows, or just a plain cup.  Our goal when sizing the cups to the parts is to ensure they are going to engage the surface in a solid secure manner that makes the lifting rig safe and stable to use.

For example, take a look at this solar lens manufacturer who utilizes many EXAIR products in this pick and place operation.

If you would like to discuss your Adjustable E-Vac, Vacuum Cup, or heavy lifting, please contact me.

Brian Farno
Application Engineer
@EXAIR_BF
BrianFarno@EXAIR.com

 

The 2020 ASF Media Room – Arnold Sports Festival, 2020 – https://www.arnoldsportsfestival.com/visitor-info/media/